This invention relates to a power nutrunner of the type having an adjustable torque release clutch.
In particular, the invention concerns a power nutrunner which comprises a planetary reduction gearing with a ring gear, and a torque release clutch associated with the ring gear, wherein the release clutch includes a thrust element, a cam means, and a pretensioned spring acting between a spring support means movably supported in the housing and the thrust element for exerting an adjustable release point determining bias load on the cam means.
A power nutrunner of this type is previously known through U.S. Pat. No. 4,084,487. The pretension level of the clutch biassing spring of this power tool is adjustable by a ring nut which engages an external thread on the tool housing. This ring nut is normally covered by a protective exhaust deflector sleeve, and setting of the clutch spring pretension level is rather awkward, since the protective sleeve has to be released and slid aside to get access to the ring nut. This prior art spring support design is disadvantageous also in that it adds to the outer dimensions of the nutrunner housing.
The main object of the invention is to provide a power nutrunner of the above described type, wherein the clutch spring support means is compact in design, easily accessible by means of a setting tool without dismantling any tool parts, and still well protected against unintentional displacement.
Another object of the invention is to provide a setting tool specially adapted for the adjustable clutch spring support means having the specific features of the invention.
Further objects and advantages of the invention will appear from the following specification and claims.
A preferred embodiment of the invention is below described in detail with reference to the accompanying drawing figures.